Device To-Be-Charged, Wireless Charging Apparatus, and Wireless Charging Method

ABSTRACT

A device to-be-charged, a wireless charging apparatus and method are provided. The apparatus includes: a voltage converting circuit, configured to receive an input voltage and convert the input voltage to obtain an output voltage and an output current of the voltage converting circuit; a wireless transmitting circuit, configured to transmit an electromagnetic signal according to the output voltage and the output current of the voltage converting circuit to conduct wireless charging on a device to-be-charged; and a first control circuit, configured for wireless communication with the device to-be-charged during the wireless charging to acquire an output voltage and/or an output current of a step-down circuit fed back by the device to-be-charged, and adjust the output voltage and/or the output current of the voltage converting circuit according to the output voltage and/or the output current of the step-down circuit to adjust a transmission power of the electromagnetic signal.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of International Patent ApplicationNo. PCT/CN2018/082011, filed on Apr. 4, 2018, which claims priority toInternational Patent Application No. PCT/CN2017/079784, filed on Apr. 7,2017 and International Patent Application No. PCT/CN2017/080334, filedon Apr. 13, 2017, the disclosures of all of which are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

This disclosure relates to the field of charging and more particularly,to a device to-be-charged, a wireless charging apparatus, and a wirelesscharging method.

BACKGROUND

With popularity of wireless charging, an increasing number of electronicdevices support a wireless charging function. The manner of wirelesselectrical power/energy transfer in wireless charging technologyincludes electromagnetic induction, electromagnetic resonance, andelectromagnetic radiation. Taking wireless charging technology based onelectromagnetic induction as an example, the principle of wirelesselectrical power transfer based on electromagnetic induction lies inthat, energy transfer is conducted through coil coupling and atransmitting end and a receiving end are respectively provided with acoil. The transmitting end is coupled with a high frequency alternatingsignal to generate an electromagnetic signal. The receiving end convertsthrough a coil the electromagnetic signal received into a current. Thecurrent is used for providing electrical power to a device after beingsubjected to processing of a rectifier circuit, a voltage stabilizingcircuit, etc.

In the case of wireless charging technology, an interface of a deviceto-be-charged which is configured to be coupled with a charging cablecan be removed, and it is unnecessary to be coupled with a cable forcharging, which makes charging more convenient.

However, wireless charging technology in the related art has at least adisadvantage of serious heating in wireless charging.

SUMMARY

In a first aspect of the present disclosure, a wireless chargingapparatus is provided. The wireless charging apparatus includes avoltage converting circuit, a wireless transmitting circuit, and a firstcontrol circuit. The voltage converting circuit is configured to receivean input voltage and convert the input voltage to obtain an outputvoltage and an output current of the voltage converting circuit. Thewireless transmitting circuit is configured to transmit anelectromagnetic signal according to the output voltage and the outputcurrent of the voltage converting circuit to conduct wireless chargingon a device to-be-charged. The first control circuit is configured forwireless communication with the device to-be-charged during the wirelesscharging to acquire at least one of an output voltage and an outputcurrent of a step-down circuit fed back by the device to-be-charged, andadjust at least one of the output voltage and the output current of thevoltage converting circuit according to at least one of the outputvoltage and the output current of the step-down circuit to adjust atransmission power of the electromagnetic signal, to make a voltagedifference between an input voltage of the step-down circuit and theoutput voltage of the step-down circuit meet a preset condition.

In a second aspect of the present disclosure, a device to-be-charged isprovided. The device to-be-charged includes a battery, a wirelessreceiving circuit, a step-down circuit, a detecting circuit, and asecond control circuit. The wireless receiving circuit is configured toreceive an electromagnetic signal from a wireless charging apparatus andconvert the electromagnetic signal into an output voltage and an outputcurrent of the wireless receiving circuit. The step-down circuit isconfigured to receive the output voltage of the wireless receivingcircuit and decrease the output voltage of the wireless receivingcircuit to charge the battery. The detecting circuit is configured todetect at least one of an output voltage and an output current of thestep-down circuit. The second control circuit is configured tocommunicate with the wireless charging apparatus according to at leastone of the output voltage and the output current of the step-downcircuit detected by the detecting circuit, whereby the wireless chargingapparatus adjusts a transmission power of the electromagnetic signal tomake a voltage difference between an input voltage of the step-downcircuit and the output voltage of the step-down circuit meet a presetcondition.

In a third aspect of the present disclosure, a wireless charging methodis provided. The wireless charging method is applicable to a deviceto-be-charged and includes the following. A wireless receiving circuitreceives an electromagnetic signal from a wireless charging apparatusand converts the electromagnetic signal into an output voltage and anoutput current of the wireless receiving circuit. A step-down circuitreceives the output voltage of the wireless receiving circuit anddecreases the output voltage of the wireless receiving circuit to chargea battery of the device to-be-charged. At least one of an output voltageand an output current of the step-down circuit is detected. Communicatewith the wireless charging apparatus according to at least one of theoutput voltage and the output current of the step-down circuit detected,whereby the wireless charging apparatus adjusts a transmission power ofthe electromagnetic signal.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are provided for better understanding of thepresent disclosure and form a part of the specification. In connectionwith implementations of the disclosure below, the accompanying drawingsare used for explaining rather than limiting the disclosure.

FIG. 1 is a schematic diagram of a wireless charging system according toan implementation of the present disclosure.

FIG. 2 is a structural block diagram of a wireless charging apparatusaccording to an implementation of the present disclosure.

FIG. 3 is a structural block diagram of a device to-be-charged accordingto an implementation of the present disclosure.

FIG. 4 is a structural block diagram of a device to-be-charged accordingto another implementation of the present disclosure.

FIG. 5 is a schematic flowchart of communication between a wirelesscharging apparatus and a device to-be-charged according to animplementation of the present disclosure.

FIG. 6 is a schematic flowchart of wireless charging according to animplementation of the present disclosure.

FIG. 7 is a schematic flowchart of a wireless charging method accordingto an implementation of the present disclosure.

FIG. 8 is a schematic flowchart of a wireless charging method accordingto another implementation of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, implementations of the disclosure will be described indetail with reference to the accompanying drawings. It is to beunderstood that, the implementations described below are merely forillustrating and explaining, rather than limiting, the disclosure.

The term “circuit” used in this disclosure refers to all of thefollowing: (a) hardware-only circuit implementations (such as only inanalog and/or digital circuits); (b) a combination of circuits andsoftware (and/or firmware), such as (if applicable): (i) a combinationof processor(s) or (ii) a portion of processor(s)/software (includingdigital signal processor(s)), software, and memory(s) that work togetherto cause a device such as a mobile phone or server to perform variousfunctions; (c) a circuit of microprocessor(s) or a portion ofmicroprocessor(s) that requires software or firmware for operation, evenif the software or firmware does not physically exist. This definitionof “circuit” is applicable to all uses of this term in this disclosureincluding any of the claims.

In implementations of the present disclosure, the device to-be-chargedcan be a terminal. The “terminal” can include but is not limited to adevice coupled via a wired line and/or a wireless interface toreceive/transmit communication signals. Examples of the wired line mayinclude, but are not limited to, at least one of a public switchedtelephone network (PSTN), a digital subscriber line (DSL), a digitalcable, a direct connection cable, and/or other data connection lines ornetwork connection lines. Examples of the wireless interface mayinclude, but are not limited to, a wireless interface with a cellularnetwork, a wireless local area network (WLAN), a digital televisionnetwork (such as a digital video broadcasting-handheld (DVB-H) network),a satellite network, an amplitude modulation-frequency modulation(AM-FM) broadcast transmitter, and/or with other communicationterminals. A communication terminal configured to communicate via awireless interface may be called a “wireless communication terminal”, a“wireless terminal”, and/or a “mobile terminal”. Examples of a mobileterminal may include, but are not limited to, a satellite or cellulartelephone, a personal communication system (PCS) terminal capable ofcellular radio telephone, data processing, fax, and/or datacommunication, a personal digital assistant (PDA) equipped with radiotelephone, pager, Internet/Intranet access, web browsing, notebook,calendar, and/or global positioning system (GPS) receiver, and aconventional laptop or a handheld receiver or other electronic devicesequipped with radio telephone transceiver. In addition, inimplementations of the present disclosure, the device to-be-charged orterminal can also include a power bank. The power bank can be charged bya wireless charging apparatus and thus store energy to charge otherelectronic devices.

FIG. 1 is a schematic diagram of a wireless charging system according toan implementation of the present disclosure.

The wireless charging system 10 includes a power supply device 100, awireless charging apparatus 200, and a device to-be-charged 300.

In an implementation, the power supply device 100 is configured toprovide direct current (DC) to the wireless charging apparatus 200. Thepower supply device 100 includes a rectifier circuit, a transformercircuit, a control circuit, and a charging interface, such that analternating current (AC) input can be converted into a DC output to beprovided to the wireless charging apparatus 200. For example, the powersupply device can be an adaptor, a power bank, a vehicle power supply,or the like.

In another implementation, the power supply device 100 provides directlyan AC to the wireless charging apparatus 200. For example, the powersupply device 100 can be an AC power supply. When the power supplydevice 100 is an AC power supply, the wireless charging apparatus 200further includes a circuit or module for converting the AC into a DC,such as a rectifier-filter circuit, a DC/DC converter, and the like.

The wireless charging apparatus 200 is configured to convert the DC orAC provided by the power supply device 100 into an electromagneticsignal for power delivery in a wireless manner.

As illustrated in FIG. 2, in an implementation, the wireless chargingapparatus 200 includes a rectifier-filter circuit (not illustrated), aDC/DC converter (not illustrated), a wireless transmitting circuit 201,and a first control circuit 202.

A 220V (volt) AC is converted into a steady DC with the rectifier-filtercircuit, and the DC is then subjected to conversion of the DC/DCconverter to be adjusted to a voltage having a fixed magnitude to beprovided to the wireless transmitting circuit 201.

It is to be understood that, the rectifier-filter circuit and the DC/DCconverter are optional. As mentioned above, when the power supply device100 is an AC power supply, the wireless charging apparatus 200 can beprovided with the rectifier-filter circuit and the DC/DC converter. Whenthe power supply device 100 can provide a steady DC, therectifier-filter circuit and/or the DC/DC converter can be removed.

The wireless transmitting circuit 201 is configured to convert a DCprovided by the DC/DC converter or the power supply device into an ACthat can be coupled to a transmitting coil, and the AC is then convertedthrough the transmitting coil into an electromagnetic signal fortransmission.

In an implementation, the wireless transmitting circuit 201 includes aninverter circuit and a resonant circuit. The inverter circuit includesmultiple switch transistors. An output power can be adjusted bycontrolling turn-on time (duty cycle) of the switch transistor. Theresonant circuit is configured to transfer electrical power out. Forinstance, the resonant circuit includes a capacitor and a transmittingcoil. By adjusting a resonant frequency of a switch transistor of theresonant circuit, an output power of the wireless transmitting circuit201 can be adjusted.

In an example, the wireless charging apparatus 200 can be a wirelesscharging base or a device with an power storage function. When thewireless charging apparatus 200 is a device with an power storagefunction, the wireless charging apparatus 200 further includes an powerstorage module (such as a lithium battery 305), which can obtainelectrical power/energy from an external power supply device forstorage, such that the power storage module can provide the electricalpower to the wireless transmitting circuit 201. It should be understoodthat, the wireless charging apparatus 200 can obtain electrical powerfrom the external power supply device in a wired or wireless manner. Interms of the wired manner, for example, the wireless charging apparatus200 is coupled with the external power supply device via a charginginterface (such as a Type-C interface) to obtain electrical power. Interms of the wireless manner, for example, the wireless chargingapparatus 200 includes a wireless receiving circuit similar to thatillustrated in FIG. 3, which can obtain electrical power wirelessly froma device with a wireless charging function.

The first control circuit 202 is configured to control wirelesscharging. For instance, the first control circuit 202 may communicatewith the power supply device to determine an output voltage and/or anoutput current of the power supply device, or may communicate with adevice to-be-charged to exchange charging information (such as a voltageof a battery 305 of the device to-be-charged, a temperature of thebattery 305, a charging mode, or the like) and to determine chargingparameters (such as a charging voltage and/or a charging current) forwireless charging.

It should be understood that, the wireless charging apparatus 200 canfurther include other related hardware, logic components, circuits,and/or codes for achieving respective functions. For example, thewireless charging apparatus 200 further includes a display module (suchas a light emitting diode (LED) or an LED display screen), which isconfigured to display in real time a charging state (for example, incharging, or charging completed) during wireless charging.

As illustrated in FIG. 2, in an implementation, the wireless chargingapparatus 200 further includes a voltage converting circuit 203. Thevoltage converting circuit 203 is configured to conduct voltageconversion on a voltage provided to the wireless transmitting circuit201 when the voltage provided to the wireless transmitting circuit 201does not satisfy a preset condition. For example, the voltage conversioncan be increasing voltage or decreasing voltage and accordingly, thevoltage converting circuit 204 can be implemented as a step-up circuitor step-down circuit. As mentioned above, in an example, the currentprovided to the wireless transmitting circuit 201 may be provided by theDC/DC converter, the power supply device, or the power storage moduledescribed above.

Alternatively, when the voltage provided to the wireless transmittingcircuit 201 can meet requirements on input voltage of the wirelesstransmitting circuit 201, the voltage converting circuit 203 can beomitted, to simplify the implementation of the wireless chargingapparatus. Requirements on input voltage of the wireless transmittingcircuit 201 can be set according to actual needs, for example, the inputvoltage required can be set to 10V.

In an example, the expression “the voltage of the current provided tothe wireless transmitting circuit 201 does not satisfy the presetcondition” can be comprehended as follows. Such a voltage is lower orhigher than a voltage required by the wireless transmitting circuit 201.For instance, the wireless charging is conducted in a charging mode ofhigh-voltage and small-current (such as 20V/1 A), and such a mode hashigh requirements on input voltage (such as 10V or 20V) of the wirelesstransmitting circuit 201. If the voltage provided to the wirelesstransmitting circuit 201 is unable to reach the input voltage requiredby the wireless transmitting circuit 201, the voltage converting circuit203 will increase the input voltage to meet requirements on inputvoltage of the wireless transmitting circuit 201. If an output voltageof the power supply device is higher than the input voltage required bythe wireless transmitting circuit 201, the voltage converting circuit203 will decrease the input voltage to meet requirements on inputvoltage of the wireless transmitting circuit 201.

In an implementation, as illustrated in FIG. 3, a device to-be-charged300 includes a wireless receiving circuit 301, a second control circuit302, a step-down circuit 303, a detecting circuit 304, a battery 305,and a first charging channel 306.

In an example, the wireless receiving circuit 301 is configured toconvert, through a receiving coil, an electromagnetic signal transmittedby the wireless transmitting circuit 201 of the wireless chargingapparatus 200 into an AC and conduct rectification and/or filtering onthe AC to convert the AC into a steady DC, to charge the battery 305.

In an example, the wireless receiving circuit 301 includes a receivingcoil and an AC/DC converter 307. The AC/DC converter 307 is configuredto convert an AC received by the receiving coil into a DC.

In an example, the battery 305 may include one single cell or multiplecells. When the battery 305 includes multiple cells, the multiple cellsare coupled in series. As such, a charging voltage that the battery 305can accept is a sum of charging voltages that the multiple cells canaccept respectively, which is possible to increase the charging speedand reduce heating during charging.

For example, the device to-be-charged is a mobile phone. When thebattery 305 of the device to-be-charged includes one single cell, avoltage of the single cell is generally 3.0V to 4.35V. However, when thebattery 305 of the device to-be-charged includes two cells coupled inseries, a total voltage of the two cells coupled in series is 6.0V to8.7V. Therefore, compared with one single cell, when the battery 305includes multiple cells coupled in series, an output voltage of thewireless receiving circuit 301 can be increased. To reach an equalcharging speed, a charging current required by multiple cells isapproximately 1/N times a charging current required by one single cell,where N is the number of cells coupled in series in the deviceto-be-charged. In other words, under a condition of an equal chargingspeed (that is, an equal charging power), by adopting multiple cells, itis possible to decrease the charging current, thereby reducing heatingof the device to-be-charged during charging. On the other hand, comparedwith one single cell, under a condition of an equal charging current, byadopting multiple cells, a charging voltage can be increased, therebyincreasing the charging speed.

In an example, the first charging channel 306 can be a wire. The firstcharging channel 306 can be provided with the step-down circuit 303.

The step-down circuit 303 is configured to decrease a voltage of a DCoutputted by the wireless receiving circuit 301 to obtain an outputvoltage and an output current of the first charging channel 306. In anexample, a voltage value and a current value of a DC outputted by thefirst charging channel 306 meet charging requirements of the battery305, and thus the DC outputted by the first charging channel 306 can bedirectly applied to the battery 305.

The detecting circuit 304 is configured to detect a voltage value and/ora current value of the first charging channel 306. The voltage valueand/or the current value of the first charging channel 306 may be avoltage value and/or a current value between the wireless receivingcircuit 301 and the step-down circuit 303, that is, an output voltagevalue and/or an output current value of the wireless receiving circuit301. Alternatively, the voltage value and/or the current value of thefirst charging channel 306 may be a voltage value and/or a current valuebetween the step-down circuit 303 and the battery 305, that is, anoutput voltage and/or an output current of the step-down circuit 303.

In an example, the detecting circuit 304 includes a voltage detectingcircuit 304A and a current detecting circuit 304B. The voltage detectingcircuit 304A is configured to sample a voltage in the first chargingchannel 306 and transmit sampled voltage value to the second controlcircuit 302. In some examples, the voltage detecting circuit 304A isconfigured to sample the voltage in the first charging channel 306 byvoltage division in series. The current detecting circuit 304B isconfigured to sample a current in the first charging channel 306 andtransmit sampled current value to the second control circuit 302. Insome examples, the current detecting circuit 304B is configured tosample and/or detect the current in the first charging channel 306 via acurrent sensing resistor and a current detector.

In an example, the second control circuit 302 is configured tocommunicate with the first control circuit 202 of the wireless chargingapparatus and feed back a voltage value and/or a current value detectedby the detecting circuit 304 to the first control circuit 202. As such,the first control circuit 202 can adjust the transmission power of thewireless transmitting circuit 201 according to the voltage value and/orthe current value fed back, to make the voltage value and/or the currentvalue of the DC outputted by the first charging channel 306 match acharging voltage value and/or a charging current value required by thebattery 305.

It is to be understood that, in an example, the expression “match thecharging voltage value and/or the charging current value required by thebattery 305” can be comprehended as follows. The voltage value and/orthe current value of the DC outputted by the first charging channel 306is equal to the charging voltage value and/or the charging current valuerequired by the battery 305, or a difference between the voltage valueand/or the current value of the DC outputted by the first chargingchannel 306 and the charging voltage value and/or the charging currentvalue required by the battery 305 is within a preset range (for example,the voltage value is 100 mV-200 mV higher or lower than the chargingvoltage value required).

In implementations of the disclosure, the step-down circuit 303 can beimplemented in various forms. In an implementation, the step-downcircuit 303 is a Buck circuit. In another implementation, the step-downcircuit 303 is a charge pump. The charge pump is composed of multipleswitch components. Heat produced when current flows through the multipleswitch components is small, almost the same as heat produced whencurrent flows directly through a wire. Therefore, by adopting the chargepump as the step-down circuit 303, not only can voltage be decreased,but also heating is low. In an example, the step-down circuit 303 canalso be a half voltage circuit.

In an example, a step-up factor of the voltage converting circuit 203 ofthe wireless charging apparatus 200 and a step-down factor of the stepdown circuit 303 of the device to-be-charged 300 depend on an outputvoltage that the power supply device is able to provide, a chargingvoltage required by the battery 305, or the like. The step-up factor ofthe voltage converting circuit 203 may or may not be equal to thestep-down factor of the step down circuit 303, which is not particularlylimited herein.

As an example, the step-up factor of the voltage converting circuit 203is equal to the step-down factor of the step-down circuit 303. Forexample, the voltage converting circuit 203 is a voltage multipliercircuit (also known as a voltage doubler circuit or doubler circuit)configured to double the output voltage of the power supply device. Thestep-down circuit 303 is a half voltage circuit configured to decreasethe output voltage of the wireless receiving circuit 301 by half.

In this example, the step-up factor of the voltage converting circuit203 is set to be equal to the step-down factor of the step-down circuit303. As such, the output voltage and the output current of the step-downcircuit 303 are equal to the output voltage and the output current ofthe power supply device respectively, which is beneficial to simplifyingthe structure of control circuits 202 and 302. As an example, a chargingcurrent required by the battery 305 is 5 A. When the second controlcircuit 302 knows through the detecting circuit 304 that the outputcurrent of the step-down circuit 303 is 4.5 A, it is necessary to adjustan output power of the power supply device to make the output current ofthe step-down circuit 303 reach 5 A. If the step-up factor of thevoltage converting circuit 203 is not equal to the step-down factor ofthe step-down circuit 303, when the output power of the power supplydevice is adjusted, it is necessary for the first control circuit 202 orthe second control circuit 302 to re-calculate an adjustment range ofthe output power of the power supply device according to a differencebetween a present output current of the step-down circuit 303 and anexpected output current. In this example, the step-up factor of thevoltage converting circuit 203 is set to be equal to the step-downfactor of the step-down circuit 303, in this way, the second controlcircuit 302 can simply instruct the first control circuit 202 toincreasing the output current of the power supply device to 5 A, therebysimplifying feedback adjustment of a wireless charging path.

As illustrated in FIG. 4, in an example, the device to-be-charged 300further includes a second charging channel 308. The second chargingchannel 308 can be a wire. The second charging channel 308 can beprovided with a converting circuit 307 configured to conduct voltagecontrol on the DC outputted by the wireless receiving circuit 301 toobtain an output voltage and an output current of the second chargingchannel 308 to charge the battery 305.

In an example, the converting circuit 307 includes a circuit for voltagestabilization (such as a voltage stabilizing circuit) and a circuit forachieving constant current and constant voltage. The voltage stabilizingcircuit is coupled with the wireless receiving circuit 301. The circuitfor achieving constant current and constant voltage is coupled with thebattery 305.

When the battery 305 is charged through the second charging channel 308,the transmission power of the wireless transmitting circuit 201 can beconstant. After the wireless receiving circuit 301 receives theelectromagnetic signal, the converting circuit 307 converts theelectromagnetic signal into a voltage and a current that meet chargingrequirements of the battery 305 and then inputs the converted voltageand the converted current into the battery 305 for charging. It shouldbe understood that, in some implementations, a constant transmissionpower does not necessarily refer to a transmission power that remainscompletely constant. Instead, the constant transmission power may varywithin a certain range, for example, the transmission power is 7.5 W(watt) and can fluctuate by 0.5 W.

In this example, the second control circuit 302 is further configured todetermine an error value by comparing the output voltage value of thesecond charging channel 308 detected with a preset target value (such asa voltage value required by the battery 305) and then transmit the errorvalue to a first controller in the form of data package. The outputvoltage value of the second charging channel 308 may be a voltage valuebetween the converting circuit 307 and the battery 305.

In an example, when the battery 305 is charged through the secondcharging channel 308, wireless charging between the wireless chargingapparatus and the device to-be-charged can be conducted under QIstandard. In this way, a data signal including the above error value canbe coupled, through signal modulation, to a coil of the wirelessreceiving circuit 301 to be transmitted to a coil of the wirelesstransmitting circuit 201 and then to the first controller.

In another example, when the battery 305 is charged through the secondcharging channel 308, wireless transfer of electrical power can becontrolled as follows.

The second control circuit 302 determines an error value by comparingthe output voltage value of the second charging channel 308 detectedwith a preset target value and then transmits the error value to a firstcontroller in the form of data package. The first controller determinesa difference according to a present current value of a transmitting coiland information of the data package including the error value anddetermines, according to the difference, a new working frequency toadjust the transmission power of the wireless transmitting circuit 201.

In implementations of the disclosure, a charging mode in which thebattery 305 is charged through the first charging channel 306 isreferred to as a first charging mode, and a charging mode in which thebattery 305 is charged through the second charging channel 308 isreferred to as a second charging mode. The wireless charging apparatuscan communicate with the device to-be-charged to determine to enable thefirst charging mode or the second charging mode to charge the battery305.

In implementations of the disclosure, at the wireless chargingapparatus, when the device to-be-charged is charged in the firstcharging mode, a maximum transmission power of the wireless transmittingcircuit 201 can be a first transmission power (value). When the deviceto-be-charged is charged in the second charging mode, the maximumtransmission power of the wireless transmitting circuit 201 can be asecond transmission power (value). The first transmission power (value)is higher than the second transmission power (value), such that a speedat which the device to-be-charged is charged in the first charging modeis higher than that in the second charging mode.

As described above, in an example, to reduce heating of a coil duringwireless charging, in the first charging mode, the wireless transmittingcircuit 201 can adopt a high voltage and a small current, that is, anoutput voltage of the wireless transmitting circuit 201 in the firstcharging mode is higher than that in the second charging mode, such thatthe first transmission power (value) is higher than the secondtransmission power (value).

At the device to-be-charged, the second control circuit 302 controlsswitching between the first charging channel 306 and the second chargingchannel 308 according to the charging mode. When the first charging modeis enabled, the second control circuit 302 controls the step-downcircuit 303 in the first charging channel 306 to work. When the secondcharging mode is enabled, the second control circuit 302 controls theconverting circuit 307 in the second charging channel 308 to work.

In implementations of the disclosure, the wireless charging apparatusdoes not charge the device to-be-charged indiscriminately in the firstcharging mode or in the second charging mode. Instead, the wirelesscharging apparatus conducts a two-way communication with the deviceto-be-charged to negotiate for use of the charging mode, which makes acharging process safer.

FIG. 5 is a schematic flowchart of communication between a wirelesscharging apparatus and a device to-be-charged according to animplementation of the present disclosure.

At S51, a wireless charging apparatus sends a first instruction to adevice to-be-charged.

The first instruction is used for enquiring whether the deviceto-be-charged is operable in a first charging mode or requesting atleast one of the following information of the device to-be-charged: atype or a model of the device to-be-charged (for example, a model setbefore leaving the factory), an identification code of the deviceto-be-charged (such as a character string preset for the deviceto-be-charged indicative of whether the device to-be-charged is operablein or supports the first charging mode), a maximum charging voltage anda maximum charging current supported by the device to-be-charged, etc.As described above, the maximum charging voltage and the maximumcharging current supported by the device to-be-charged relate to circuitparameters of the step-down circuit 303 or the converting circuit 307 ofthe device to-be-charged and/or the number of cells in the battery 305of the device to-be-charged.

At S52, the wireless charging apparatus determines a charging mode foruse according to a response message fed back by the deviceto-be-charged.

In an example, when the response message indicates that the deviceto-be-charged is operable in the first charging mode, the wirelesscharging apparatus determines to enable the first charging mode. On thecontrary, when the response message indicates that the deviceto-be-charged is not operable in the first charging mode, the wirelesscharging apparatus determines to enable a second charging mode.

The response message fed back by the device to-be-charged includes atleast one of: the type or model of the device to-be-charged, theidentification code of the device to-be-charged, the maximum chargingvoltage and the maximum charging current supported by the deviceto-be-charged, etc. The wireless charging apparatus determines thecharging mode for use according to the response message received. Forexample, when the type or model of the device to-be-charged indicatesthat the device to-be-charged is operable in the first charging mode,the wireless charging apparatus determines to use the first chargingmode to conduct wireless charging on the device to-be-charged.

In an example, the wireless charging apparatus feeds back the chargingmode determined to the device to-be-charged, such that the deviceto-be-charged can control on-off states of the first charging channel306 or the second charging channel 308.

In an implementation, communication between the wireless chargingapparatus and the device to-be-charged can be Bluetooth communication,wireless fidelity (Wi-Fi) communication, near field communication (NFC)based on a high carrier frequency, optical communication, ultrasoniccommunication, ultra-wideband communication, or mobile communication.

In an example, an NFC module based on a high carrier frequency includesan integrated circuit (IC) chip with an extremely high frequency (EHF)antenna encapsulated. As an example, the high carrier frequency is 60GHz.

In an example, an optical communication module includes an infraredcommunication module. The infrared communication module can transmitinformation with an infrared ray.

In an example, a mobile communication module can transmit informationbased on the fifth-generation (5G) communication protocol, the 4Gcommunication protocol, the 3G communication protocol, and other mobilecommunication protocols.

Compared with the forgoing communication manner in which the data signalis coupled to the coil of the wireless receiving circuit 301 throughsignal modulation, by adopting the above wireless communication manner,communication can be more reliable. In addition, voltage ripples causedby communication in a signal coupling manner can be avoided, and suchvoltage ripples can affect voltage processing of the converter circuit307 or the step-down circuit 303.

In implementations of the disclosure, besides communicating with thedevice to-be-charged to determine a charging mode between the wirelesscharging apparatus and the device to-be-charged, the wireless chargingapparatus can also communicate with a power supply device to determine acharging mode between the power supply device and the wireless chargingapparatus.

As mentioned above, a transmission power of the wireless chargingapparatus in the first charging mode is higher than that in the secondcharging mode, that is, a voltage required by the wireless transmittingcircuit 201 of the wireless charging apparatus in the first chargingmode is higher. Therefore, the wireless charging apparatus cancommunicate with the power supply device to make the power supply deviceprovide a suitable voltage.

In an example, the power supply device can be a quick-charging powersupply device and a non-quick-charging power supply device. An outputvoltage that the quick-charging power supply device is able to provideis higher than an output voltage that the non-quick-charging powersupply device is able to provide. For example, an output voltage/anoutput current of the non-quick-charging power supply device is 5V/2 A,and an output voltage/an output current of the quick-charging powersupply device is 15V/2 A.

When the power supply device is the quick-charging power supply device,a voltage provided to the wireless charging apparatus by the powersupply device can make the wireless charging apparatus be operable inthe first charging mode. When the power supply device is thenon-quick-charging power supply device, the voltage provided to thewireless charging apparatus by the power supply device can make thewireless charging apparatus be operable in the second charging mode.

In an implementation, the wireless charging apparatus communicates withthe power supply device to determine a type of the power supply device,communicates with the device to-be-charged in the communication mannergiven above to determine a charging mode in which the deviceto-be-charged is operable, and determines a charging mode for useaccording to the type of the power supply device and/or the chargingmode in which the device to-be-charged is operable.

In an implementation, when the power supply device is thenon-quick-charging power supply device and the device to-be-charged isoperable in the first charging mode, the wireless charging apparatus canconvert, with the voltage converting circuit 203, a voltage provided bythe power supply device to enable the first charging mode.

In another example, when the power supply device is the quick-chargingpower supply device and the device to-be-charged is operable in thefirst charging mode, if a voltage provided by the power supply device isunable to meet requirements of the wireless transmitting circuit 201(that is, requirements on voltage of the wireless transmitting circuit201 in the first charging mode), the wireless charging apparatus canstill convert, with the voltage converting circuit 203, the voltageprovided by the power supply device to enable the first charging mode.

In another example, when the power supply device is the quick-chargingpower supply device but the device to-be-charged is operable only in thesecond charging mode (for example, the device to-be-charged includesonly the second charging channel 308), the voltage converting circuit203 can convert the voltage provided by the power supply device (forexample, decrease the voltage provided by the power supply device) toenable the second charging mode.

In another example, when the power supply device is thenon-quick-charging power supply device and the device to-be-charged isoperable in the second charging mode, the wireless charging apparatusdetermines to enable the second charging mode.

When the wireless charging apparatus charges the battery 305 of thedevice to-be-charged in the first charging mode, in order to solveproblems of heating and low charging efficiency due to use of a wirelesscharging manner of low-voltage and large-current in the related art,implementations of the disclosure adopt a wireless charging manner ofhigh-voltage and small-current to reduce heating and improve chargingefficiency.

In an example, the wireless charging apparatus is provided with thevoltage converting circuit 203. The device to-be-charged is providedwith the first charging channel 306 (such as a wire) coupled with thebattery 305. The first charging channel 306 is provided with thestep-down circuit 303 configured to decrease the output voltage of thewireless receiving circuit 301 to make an output voltage and an outputcurrent of the first charging channel 306 meet charging requirements ofthe battery 305.

In an example, the wireless charging apparatus 200 uses a 20 W outputpower to charge the battery 305 with one single cell of the deviceto-be-charged. In this case, when the battery 305 with one single cellis charged through the second charging channel 308, an input voltage ofthe wireless transmitting circuit 201 is required to be 5V, and an inputcurrent of the wireless transmitting circuit 201 is required to be 4 A.However, a 4 A current used will certainly result in heating of a coil,which reduces charging efficiency.

When the battery 305 with one single cell is charged through the firstcharging channel 306, since the first charging channel 306 is providedwith the step-down circuit 303, under a condition that the transmissionpower of the wireless transmitting circuit 201 remains unchanged (theabove-mentioned 20 W), the input voltage of the wireless transmittingcircuit 201 can be increased, such that the input current of thewireless transmitting circuit 201 can be decreased.

In an example, the step-down circuit 303 is a half voltage circuit, thatis, an input voltage of the step-down circuit 303 is twice the outputvoltage of the step-down circuit 303, thereby further reducing heatingof the step-down circuit 303.

As an example, the step-down circuit 303 is the half voltage circuit. Inthis case, the input voltage of the wireless transmitting circuit 201 is10V, and the input current of the wireless transmitting circuit 201 is 2A. As such, the output voltage of the wireless receiving circuit 301 is10V (it should be understood that, considering electrical power loss, anactual output voltage of the wireless receiving circuit 301 will beclose to 10V). Through voltage decrease by the step-down circuit 303,the output voltage of the first charging channel 306 is 5V to charge thebattery 305. It is to be understood that, in this example, the voltagerequired by the battery 305 is 5V. In practice, when the battery 305 ischarged, the second control circuit 302 feeds back the output voltageand/or the output current of the step-down 303 detected in real time bythe detecting circuit 304 to the first control circuit 202. The firstcontrol circuit 202 adjusts, according to the output voltage and/or theoutput current fed back, the output power of the wireless transmittingcircuit 201 to make a voltage difference between the input voltage ofthe step-down 303 and the output voltage of the step-down 303 satisfy apreset condition.

In implementations of the disclosure, the manner in which the wirelesscharging apparatus 200 adjusts the output power of the wirelesstransmitting circuit 201 can be various, which may include any one ormore of the following three manners.

(1) Under a condition that a voltage input into the wirelesstransmitting circuit 201 has a fixed magnitude or constant, the outputpower of the wireless transmitting circuit 201 is adjusted by adjustinga tuning frequency of a resonant circuit and/or a duty ratio of a switchtransistor of an inverter circuit.

(2) The output power of the wireless transmitting circuit 201 isadjusted by adjusting an output voltage of the voltage convertingcircuit 203 (that is, the voltage input into the wireless transmittingcircuit 201).

(3) When the voltage converting circuit 203 illustrated in FIG. 1 isremoved, the output power of the wireless transmitting circuit 201 isadjusted by adjusting an output voltage of the power supply device (thatis, a voltage input into the wireless charging apparatus).

For instance, the above preset condition is that the input voltage ofthe step-down circuit 303 is twice the output voltage of the step-downcircuit 303. As such, if manner (2) described above is adopted foradjusting the output power of the wireless transmitting circuit 201,when the output voltage of the step-down circuit 303 is detected to beDIV, the first control circuit 202 controls to make the input voltage ofthe step-down circuit 303 be 2*D1V (it is to be understood that,considering energy loss, an actual input voltage of the step-downcircuit 303 can be higher than 2*D1V), such that the voltage differenceof the step-down circuit 303 satisfies the preset condition, therebyreducing heating and improving charging efficiency.

When manner (1) described above is adopted and the input voltage of thewireless transmitting circuit 201 is constantly D2, if the outputvoltage of the step-down circuit 303 is detected to be DIV, the firstcontrol circuit 202 determines the tuning frequency or the duty ratio ofthe switch transistor according to D1 and D2 to make the input voltageof the step-down circuit 303 be 2*D1V (it is to be understood that,considering energy loss, an actual input voltage of the step-downcircuit 303 can be higher than 2*D1V).

When manner (3) described above is adopted, if the output voltage of thestep-down circuit 303 is detected to be DIV, the first control circuit202 communicates with the power supply device according to D1 to make avoltage that the power supply device provides to the wirelesstransmitting circuit 201 be 2*D1V to make the output voltage of thewireless transmitting circuit 201 be 2*D1V (it is to be understood that,considering energy loss, an actual output voltage of the wirelesstransmitting circuit 201 can be higher than 2*D1V), such that the inputvoltage of the step-down circuit 303 is 2*D1V.

The manner of communication between the first control circuit 202 andthe power supply device is no limited herein. As an example, the firstcontrol circuit 202 can be coupled with and communicate with the powersupply device via another communication interface other than a charginginterface. As another example, the first control circuit 202 cancommunicate with the power supply device in a wireless manner. Forexample, the first control circuit 202 can conduct an NFC with the powersupply device. As yet another example, the first control circuit 202 cancommunicate with the power supply device via the charging interfacewithout providing any extra communication interface or another wirelesscommunication module, which can simplify the implementation of thewireless charging apparatus. For instance, the charging interface is auniversal serial bus (USB) interface. The first control circuit 202 cancommunicate with the power supply device via a data line (such as a D+line and/or a D− line) of the USB interface. For another instance, thecharging interface is a USB interface supporting a power delivery (PD)communication protocol (such as a USB TYPE-C interface). The firstcontrol circuit 202 can communicate with the power supply device basedon the PD communication protocol.

The manner in which the power supply device adjusts its own output poweris not limited herein. For example, the power supply device can beprovided with a voltage feedback loop and a current feedback loop toadjust the output voltage and/or the output current of the power supplydevice according to actual needs.

In an example, the wireless charging apparatus 200 can be in variousshapes, such as a circular shape, a rectangular shape, etc. When thedevice to-be-charged is placed on a charging surface (a surface providedwith a transmitting coil) of the wireless charging apparatus 200, thewireless charging apparatus 200 begins wireless charging in a wirelesscharging procedure illustrated in FIG. 6.

FIG. 6 is a schematic flowchart of wireless charging according to animplementation of the present disclosure.

At S61, the wireless charging apparatus detects existence of an object.

For example, the wireless charging apparatus transmits a signal at apreset time interval to detect whether an object is placed on a surfaceof the wireless charging apparatus.

At S62, the wireless charging apparatus determines whether the objectdetected is a legal (that is, proper) device to-be-charged.

At S63, the wireless charging apparatus acquires identity informationand configuration information of the device to-be-charged.

For example, the identity information may be the identification code ofthe device to-be-charged described above. The configuration informationmay be the type or model of the device to-be-charged described above.

At S64, the wireless charging apparatus determines a charging modeaccording to the identity information and the configuration informationof the device to-be-charged.

For example, the charging mode can be determined in the above manner,that is, determined according to the type of the power supply deviceand/or the charging mode in which the device to-be-charged is operable.

In implementations of the disclosure, when the second charging mode isdetermined to be enabled, wireless charging at S65 to S67 is conducted.When the first charging mode is determined to be used, wireless chargingat S68 to S69 is conducted.

At S65, control information fed back by the device to-be-charged isacquired during wireless charging.

In an example, as mentioned above, the second control circuit 302 of thedevice to-be-charged can couple a data package signal including thecontrol information to the coil of the wireless receiving circuit 301 totransmit the data package signal to the coil of the wirelesstransmitting circuit 201 and then to the first controller of thewireless charging apparatus. The control information can include theerror value described above.

At S66, when the control information indicates termination ofinformation transmission, stop wireless charging.

At S67, when the control information indicates error information, thetransmission power of the wireless transmitting circuit 201 is adjustedaccording to the error information.

For example, the transmission power can be adjusted in the manner (1) or(3) described above.

At S68, conduct wireless communication with the device to-be-chargedduring wireless charging to acquire the output voltage and/or the outputcurrent of the step-down circuit 303 fed back by the deviceto-be-charged.

At S69, the output voltage and/or the output current of the voltageconverting circuit 203 is adjusted according to the output voltageand/or the output current of the step-down circuit 303 to adjust atransmission power of an electromagnetic signal, to make the voltagedifference between the input voltage of the step-down circuit 303 andthe output voltage of the step-down circuit 303 satisfy the presetcondition.

For example, the transmission power can be adjusted in any one or moreof the above manners (1) to (3).

It should be understood that, no matter whether the first charging modeor the second charging mode is enabled, the wireless charging will stopif a charging stop condition is satisfied. For example, when the deviceto-be-charged is detected to have left the charging surface, thecharging stop condition is satisfied. Alternatively, when a chargingprocess is detected to experience abnormality (such as over-voltage,over-current, or over-temperature in the charging process), the chargingstop condition is satisfied.

In an example, when the first charging mode is enabled, the outputvoltage of the wireless receiving circuit 301 of the deviceto-be-charged depends on the output voltage of the voltage convertingcircuit 203. In an example, by decreasing the voltage difference betweenthe input voltage of the step-down circuit 303 and the output voltage ofthe step-down circuit 303, working efficiency of the step-down circuit303 can be improved and temperature rise can be reduced. In an example,since the input voltage of the step-down circuit 303 depends on an inputvoltage of the wireless receiving circuit 301, the voltage difference ofthe step-down circuit 303 can be decreased by decreasing the inputvoltage of the wireless receiving circuit 301.

It is to be understood that, the wireless charging apparatus and/or thedevice to-be-charged in implementations of the disclosure can beoperable only in the first charging mode for wireless charging, or beoperable in the first charging mode or in the second charging mode forwireless charging, which is not limited herein.

In an example, in order to keep a charging voltage of the battery 305constant, if the input voltage of the wireless receiving circuit 301 isdecreased, it is necessary to increase an input current of the wirelessreceiving circuit 301, and increase in input current will result inincrease in current in the receiving coil, which in turn makestemperature rise of the receiving coil more serious. Therefore, thefirst control circuit 202 of the wireless charging apparatus inimplementations of the disclosure can be further configured to adjustthe output voltage of the voltage converting circuit 203 according tothe output current of the step-down circuit 303 fed back by the deviceto-be-charged and a preset current threshold.

In an example, the current threshold includes a first current thresholdand a second current threshold, where the first current threshold isgreater than the second current threshold. The first control circuit 202is configured to control to increase the output voltage of the voltageconverting circuit 203 when the output current of the step-down circuit303 is larger than the first current threshold and configured to controlto decrease the output voltage of the voltage converting circuit 203when the output current of the step-down circuit 303 is smaller than thesecond current threshold.

It is to be understood that, under a condition of a constanttransmission power, when the output current of the step-down circuit 303is larger than the first current threshold, even if the voltagedifference of the step-down circuit 303 satisfies the preset condition,heating of the receiving coil will occur due to excessively largecurrent in the receiving coil. Therefore, by controlling to increase theoutput voltage of the voltage converting circuit 203, the output currentof the step-down circuit 303 will be decreased, which is beneficial toreducing heating of the receiving coil. However, when the output currentof the step-down circuit 303 is smaller than the second currentthreshold, the voltage difference of the step-down circuit 303 willincrease, which results in heating of the step-down circuit 303.Therefore, by controlling to decrease the output voltage of the voltageconverting circuit 203, the voltage difference of the step-down circuit303 will be decreased, which can reduce heating of the step-down circuit303.

In an example, a temperature rise model database can be establishedaccording to data in a debugging stage or data obtained through multipletests, to determine a maximum current threshold allowed in a chargingcoil (that is, the first current threshold described above) and todetermine the second current threshold described above.

In an example, the first control circuit 202 of the wireless chargingapparatus is further configured to adjust the output voltage of thevoltage converting circuit 203 according to the output voltage of thestep-down circuit 303 fed back by the device to-be-charged and a presetcorrespondence relationship between the voltage difference and thecharging efficiency.

In another example, a voltage difference when the step-down circuit 303operates at an optimum (for example, maximum) efficiency can be obtainedby debugging and testing according to working characteristics of thestep-down circuit 303 to determine the correspondence relationshipbetween the voltage difference and the charging efficiency. The chargingefficiency can be reflected by temperature rise, for example, thecharging efficiency is in an inverse proportion to temperature rise,that is, a higher charging efficiency corresponds to a smallertemperature rise.

In an example, the voltage difference can also be a voltage differencebetween an input voltage of the battery 305 and the output voltage ofthe voltage converting circuit 203. It should be understood that, insome examples, the voltage difference of the step-down circuit can alsobe obtained according to the voltage of the battery and any one of thefollowing voltages: the output voltage of the wireless transmittingcircuit, the output voltage of the wireless receiving circuit, the inputvoltage of the step-down circuit, and the output voltage of the voltageconverting circuit.

Therefore, the output voltage of the voltage converting circuit 203 canbe adjusted according to the voltage difference of the step-down circuit303 and the above correspondence relationship to reach the maximumcharging efficiency. Alternatively, the input voltage of the battery 305can be determined according to the output voltage of the step-downcircuit fed back. Then the output voltage of the voltage convertingcircuit 203 can be adjusted according to the voltage difference betweenthe input voltage of the battery 305 determined and the output voltageof the voltage converting circuit 203 and the above correspondencerelationship to reach the maximum charging efficiency.

In an example, the above two manners for adjusting the output voltage ofthe voltage converting circuit 203 can be combined, that is, the outputvoltage of the voltage converting circuit 203 is adjusted to be a firstvoltage according to the output voltage of the step-down circuit 303 fedback by the device to-be-charged and the preset correspondencerelationship between the voltage difference and the charging efficiency,and after the output voltage of the voltage converting circuit 203 isadjusted to be the first voltage, the output voltage of the voltageconverting circuit 203 is adjusted to be a second voltage according tothe output current of the step-down circuit 303 fed back by the deviceto-be-charged and the preset current threshold. In this way, both arough adjustment and a fine adjustment can be made to the output voltageof the voltage converting circuit 203, thereby ensuring accuracy ofadjustment.

FIG. 7 is a schematic flowchart of a wireless charging method accordingto an implementation of the present disclosure. The wireless chargingmethod is applicable to a device to-be-charged.

At S71, a wireless receiving circuit 301 receives an electromagneticsignal from a wireless charging apparatus and converts theelectromagnetic signal into an output voltage and an output current ofthe wireless receiving circuit 301.

At S72, a step-down circuit 303 receives the output voltage of thewireless receiving circuit 301 and decreases the output voltage of thewireless receiving circuit 301 to charge a battery 305 of the deviceto-be-charged.

At S73, an output voltage and/or output current of the step-down circuit303 is detected.

At S74, communicate with the wireless charging apparatus according tothe output voltage and/or the output current of the step-down circuit303, whereby the wireless charging apparatus adjusts a transmissionpower of the electromagnetic signal to make a voltage difference betweenan input voltage of the step-down circuit 303 and the output voltage ofthe step-down circuit 303 meet a preset condition.

In an example, communicating with the wireless charging apparatusaccording to an output voltage and/or an output current of the step-downcircuit 303 detected includes the following. Adjustment information issent to the wireless charging apparatus according to the output voltageand/or the output current of the step-down circuit 303 detected, wherethe adjustment information is used for instructing the wireless chargingapparatus to conduct voltage adjustment and/or current adjustment onelectrical power received from a power supply device to adjust atransmission power of the electromagnetic signal.

In an implementation, the wireless charging method includes thefollowing. A converting circuit 307 receives the output voltage and theoutput current of the wireless receiving circuit 301 and conducts aconstant-voltage control and/or a constant-current control on the outputvoltage and/or the output current of the wireless receiving circuit 301to charge the battery 305. Communicate with the wireless chargingapparatus to determine to control one of the step-down circuit 303 andthe converting circuit 307 to work.

FIG. 8 is a schematic flowchart of a wireless charging method accordingto an implementation of the present disclosure. The wireless chargingmethod is applicable to a wireless charging apparatus.

At S81, a voltage converting circuit 203 receives an input voltage andconverts the input voltage to obtain an output voltage and an outputcurrent of the voltage converting circuit 203.

At S82, a wireless transmitting circuit 201 transmits an electromagneticsignal according to the output voltage and the output current of thevoltage converting circuit 203 to conduct wireless charging on a deviceto-be-charged.

At S83, conduct wireless communication with the device to-be-chargedduring the wireless charging to acquire an output voltage and an outputcurrent of a step-down circuit 303 fed back by the device to-be-charged,and adjust at least one of the output voltage and the output current ofthe voltage converting circuit 203 according to at least one of theoutput voltage and the output current of the step-down circuit 303 toadjust a transmission power of the electromagnetic signal, to make avoltage difference between an input voltage of the step-down circuit 303and the output voltage of the step-down circuit 303 meet a presetcondition.

It should be understood that, details of operations in the above methodshave been described in foregoing implementations, which will not berepeated herein.

In implementations of the disclosure, charging on the battery 305through the first charging channel 306 or through the second chargingchannel 308 includes a trickle charging stage, a constant-currentcharging stage, and a constant-voltage charging stage. It is to be notedthat, the constant-current charging stage referred to herein does notrequire that the charging current remain completely constant, and maybe, for example, a peak value (that is, peak current) or an averagevalue of the charging current remaining constant within a certain timeperiod. Practically, in the constant-current charging stage, amulti-stage constant current charging manner is usually adopted forcharging.

Multi-stage constant current charging can include N constant-currentstages, where N is an integer not less than two (N>=2). In themulti-stage constant current charging, a first stage of charging beginswith a pre-determined charging current. The N constant-current stages ofthe multi-stage constant current charging are executed in sequence fromthe first stage to the N^(th) stage. When a previous constant-currentstage ends and a next constant-current stage begins, the chargingcurrent may be decreased. When a voltage of the battery 305 reaches athreshold of charging cut-off voltage, the multi-stage constant currentcharging proceeds to a subsequent constant-current stage, that is, theprevious constant-current stage ends and the next constant-current stagebegins. Current conversion between two adjacent constant-current stagesmay be gradual or in a step-like manner.

The manner and order of communication between the wireless chargingapparatus and the device to-be-charged are not limited herein.

In some examples, the wireless communication between the wirelesscharging apparatus and the device to-be-charged (or between the secondcontrol circuit 302 and the first control circuit 202) is a one-waywireless communication.

For example, during wireless charging of the battery 305, it can bespecified that the device to-be-charged is an initiator of communicationand the wireless charging apparatus is a receiver of communication.Exemplarily, in the constant-current charging stage of the battery 305,the device to-be-charged can detect in real time the charging current ofthe battery 305 (that is, the output current of the wireless receivingcircuit 301) through the detecting circuit 304. When the chargingcurrent of the battery 305 does not match a charging current currentlyrequired by the battery 305, the device to-be-charged can sendadjustment information to the wireless charging apparatus to instructthe wireless charging apparatus to adjust the transmission power of thewireless transmitting circuit 201.

In some examples, the wireless communication between the wirelesscharging apparatus and the device to-be-charged (or between the secondcontrol circuit 302 and the first control circuit 202) is a two-waywireless communication. The two-way wireless communication generallyrequires that the receiver sends response information to the initiatorafter receiving communication request initiated by the initiator.Two-way communication mechanism can make communication safer.

Description above does not limit master-slave relationship between thewireless charging apparatus (or the first control circuit 202 of thewireless charging apparatus) and the device to-be-charged (or the secondcontrol circuit 302 of the device to-be-charged). That is to say, anyone of the wireless charging apparatus and the device to-be-charged canfunction as a master device to initiate a two-way communication, andcorrespondingly the other one of the wireless charging apparatus and thedevice to-be-charged can function as a slave device to make a firstresponse or a first reply to the communication initiated by the masterdevice. Optionally, the master device and the slave device can bedetermined by comparing link states between the wireless chargingapparatus and the device to-be-charged. For example, suppose a wirelesslink in which the wireless charging apparatus sends information to thedevice to-be-charged is an uplink and a wireless link in which thedevice to-be-charged sends information to the wireless chargingapparatus is a downlink. When the uplink is of higher quality, thewireless charging apparatus can be determined as the master device ofcommunication. When the downlink is of higher quality, the deviceto-be-charged can be determined as the master device of communication.

The manner in which the two-way communication between the wirelesscharging apparatus and the device to-be-charged is implemented is notlimited herein. That is to say, any one of the wireless chargingapparatus and the device to-be-charged can function as the master deviceto initiate the two-way communication, and correspondingly the other oneof the wireless charging apparatus and the device to-be-charged canfunction as the slave device to make the first response or the firstreply to the communication initiated by the master device. Besides, themaster device can make a second response to the first response or thefirst reply of the slave device, and as such, the master device and theslave device complete one communication negotiation.

The master device can make the second response to the first response orthe first reply of the slave device as follows. The master devicereceives from the slave device the first response or the first reply tothe communication and makes the second response to the first response orthe first reply of the slave device.

The master device can also make the second response to the firstresponse or the first reply of the slave device as follows. When themaster device fails to receive from the slave device the first responseor the first reply to the communication within a preset time period, themaster device can still make the second response to the first responseor the first reply made by the slave device.

In some examples, after the device to-be-charged, as the master device,initiates the communication and the wireless charging apparatus, as theslave device, makes the first response or the first reply to thecommunication initiated by the master device, it can be considered thatthe wireless charging apparatus and the device to-be-charged havecompleted a communication negotiation without requiring the deviceto-be-charged to make the second response to the first response or thefirst reply of the wireless charging apparatus.

The manner of wireless communication between the first control circuit202 of the wireless charging apparatus and the second control circuit302 of the device to-be-charged is not limited herein. As an example,the first control circuit 202 can conduct wireless communication withthe second control circuit 302 based on Bluetooth, Wi-Fi, or backscattermodulation (or power load modulation).

As pointed above, during the wireless charging, the second controlcircuit 302 can be configured to conduct the wireless communication withthe first control circuit 202 according to a voltage and/or a current inthe first charging channel 306 detected by the detecting circuit 304,whereby the first control circuit 202 adjusts the transmission power ofthe wireless transmitting circuit 201. However, contents communicatedbetween the second control circuit 302 and the first control circuit 202is not limited herein.

As an example, the second control circuit 302 can send to the firstcontrol circuit 202 the output voltage and/or the output current of thefirst charging channel 306 detected by the detecting circuit 304. Inaddition, the second control circuit 302 can further send stateinformation of the battery 305 to the first control circuit 202. Thestate information of the battery 305 includes a present power and/or apresent voltage of the battery 305 of the device to-be-charged. Thefirst control circuit 202 can determine a present charging stage of thebattery 305 according to the state information of the battery 305, tofurther determine a target charging voltage and/or a target chargingcurrent that matches a charging voltage and/or the charging currentcurrently required by the battery 305. Then the first control circuit202 can compare the output voltage and/or the output current of thefirst charging channel 306 received from the second control circuit 302with the above target charging voltage and/or the above target chargingcurrent to determine whether the output voltage and/or the outputcurrent of the first charging channel 306 matches the charging voltageand/or the charging current currently required by the battery 305. Whenthe output voltage and/or the output current of the first chargingchannel 306 does not match the charging voltage and/or the chargingcurrent currently required by the battery 305, the first control circuit202 can adjust the transmission power of the wireless transmittingcircuit 201 until the output voltage and/or the output current of thefirst charging channel 306 matches the charging voltage and/or thecharging current currently required by the battery 305.

As another example, the second control circuit 302 can send adjustmentinformation to the first control circuit 202 to instruct the firstcontrol circuit 202 to adjust the transmission power of the wirelesstransmitting circuit 201. For example, the second control circuit 302can instruct the first control circuit 202 to increase the transmissionpower of the wireless transmitting circuit 201. For another example, thesecond control circuit 302 can instruct the first control circuit 202 toreduce the transmission power of the wireless transmitting circuit 201.Specifically, the wireless charging apparatus can set the transmissionpower of the wireless transmitting circuit 201 to have multiple grades.Each time the first control circuit 202 receives the adjustmentinformation, the first control circuit 202 adjusts the transmissionpower of the wireless transmitting circuit 201 by one grade until theoutput voltage and/or the output current of the first charging channel306 matches the charging voltage and/or the charging current currentlyrequired by the battery 305.

Besides the above communication content, the first control circuit 202and the second control circuit 302 can also exchange other types ofcommunication information. In some examples, the first control circuit202 and the second control circuit 302 can exchange information forsafety protection, abnormality detection, or fault handling, such astemperature information of the battery 305, information indicative ofover-voltage protection or over-current protection, etc., orpower-transmission efficiency information (for indicating efficiency inpower transmission between the wireless transmitting circuit 201 and thewireless receiving circuit 301).

For example, when the temperature of the battery 305 is excessivelyhigh, the first control circuit 202 and/or the second control circuit302 can control a charging loop to a protection state, such ascontrolling the charging loop to stop the wireless charging. For anotherexample, after receiving the information indicative of over-voltageprotection or over-current protection from the second control circuit302, the first control circuit 202 can reduce the transmission power, orcontrol the wireless transmitting circuit 201 to stop working. For yetanother example, after receiving the power-transmission efficiencyinformation from the second control circuit 302, the first controlcircuit 202 can control the wireless transmitting circuit 201 to stopworking if power-transmission efficiency is lower than a presetthreshold and notify a user of the event. Exemplarily, the fact that thepower-transmission efficiency is excessively low can be displayed via adisplay screen, or be indicated by an indicator lamp in order for theuser to adjust wireless charging environment.

In some examples, the first control circuit 202 and the second controlcircuit 302 can exchange other types of information for adjusting thetransmission power of the wireless transmitting circuit 201, such as thetemperature information of the battery 305, information indicative of apeak value or an average value of the voltage in the first chargingchannel 306, information indicative a peak value or an average value ofthe current in the first charging channel 306, the power-transmissionefficiency information (indicative of efficiency in power transmissionbetween the wireless transmitting circuit 201 and the wireless receivingcircuit 301), etc.

For instance, the second control circuit 302 can send thepower-transmission efficiency information to the first control circuit202. The first control circuit 202 can be further configured todetermine an adjustment range of the transmission power of the wirelesstransmitting circuit 201 according to the power-transmission efficiencyinformation. Specifically, when the power-transmission efficiencyinformation indicates that the efficiency in power transmission betweenthe wireless transmitting circuit 201 and the wireless receiving circuit301 is low, the first control circuit 202 can increase the adjustmentrange of the transmission power of the wireless transmitting circuit 201to make the transmission power of the wireless transmitting circuit 201reach promptly a target power.

For another instance, when the output voltage and/or the output currentof the wireless receiving circuit 301 is a pulsating waveform voltageand/or a pulsating waveform current, the second control circuit 302 cansend at least one of the information indicative of a peak value or anaverage value of the output voltage of the first charging channel 306and the information indicative of a peak value or an average value ofthe output current of the first charging channel 306 to the firstcontrol circuit 202. The first control circuit 202 can determine whetherthe peak value or the average value of the output voltage and/or theoutput current of the first charging channel 306 matches the chargingvoltage and/or the charging current currently required by the battery305. When the peak value or the average value of the output voltageand/or the output current of the first charging channel 306 does notmatch the charging voltage and/or the charging current currentlyrequired by the battery 305, the first control circuit 202 will adjustthe transmission power of the wireless transmitting circuit 201.

For yet another instance, the second control circuit 302 can send thetemperature information of the battery 305 to the first control circuit202. When a temperature of the battery 305 is excessively high, thefirst control circuit 202 will reduce the transmission power of thewireless transmitting circuit 201 to decrease the output current of thewireless receiving circuit 301, thereby reducing the temperature of thebattery 305.

Exemplary implementations of the disclosure has been described in detailabove in connection with the accompanying drawings. However, the presentdisclosure is not limited to the details of the above implementations.Various simple modifications can be made to the technical solution ofthe disclosure within the scope of the technical concept of thedisclosure, and such simple modifications shall be within the protectionscope of the present disclosure.

In addition, it is to be noted that, all the technical featuresdescribed in the above implementations can be combined with each otherin any proper manner without conflict. In order to avoid unnecessaryrepetition, various manners of combination will not be elaborated in thedisclosure.

Furthermore, various implementations of the disclosure can also berandomly combined without departing from the spirit of the presentdisclosure, and such combination should also be regarded as contentdisclosed by the present disclosure.

What is claimed is:
 1. A wireless charging apparatus, comprising: avoltage converting circuit, configured to receive an input voltage andconvert the input voltage to obtain an output voltage and an outputcurrent of the voltage converting circuit; a wireless transmittingcircuit, configured to transmit an electromagnetic signal according tothe output voltage and the output current of the voltage convertingcircuit to conduct wireless charging on a device to-be-charged; and afirst control circuit, configured for wireless communication with thedevice to-be-charged during the wireless charging to acquire at leastone of an output voltage and an output current of a step-down circuitfed back by the device to-be-charged, and adjust at least one of theoutput voltage and the output current of the voltage converting circuitaccording to at least one of the output voltage and the output currentof the step-down circuit to adjust a transmission power of theelectromagnetic signal, to make a voltage difference between an inputvoltage of the step-down circuit and the output voltage of the step-downcircuit meet a preset condition.
 2. The wireless charging apparatus ofclaim 1, wherein the first control circuit is configured to adjust theoutput voltage of the voltage converting circuit according to the outputvoltage of the step-down circuit fed back by the device to-be-chargedand a preset threshold current.
 3. The wireless charging apparatus ofclaim 2, wherein the preset threshold current comprises a firstthreshold current and a second threshold current larger than the firstthreshold current, and wherein the first control circuit is configuredto increase the output voltage of the voltage converting circuit whenthe output current of the step-down circuit is larger than the firstthreshold current and decrease the output voltage of the voltageconverting circuit when the output current of the step-down circuit issmaller than the second threshold current.
 4. The wireless chargingapparatus of claim 1, wherein the first control circuit is furtherconfigured to adjust the output voltage of the voltage convertingcircuit according to the output voltage of the step-down circuit fedback by the device to-be-charged and a correspondence relationshipbetween voltage differences and charging efficiencies.
 5. The wirelesscharging apparatus of claim 1, wherein the first control circuit isfurther configured to: adjust, according to the output voltage of thestep-down circuit fed back by the device to-be-charged and acorrespondence relationship between voltage differences and chargingefficiencies, the output voltage of the voltage converting circuit to afirst voltage, and adjust, according to the output current of thestep-down circuit fed back by the device to-be-charged and a presetthreshold current, the first voltage of the voltage converting circuitto a second voltage.
 6. The wireless charging apparatus of claim 1,wherein the voltage converting circuit is coupled with an external powersupply device; and the first control circuit is further configured tocommunicate with the external power supply device to make the externalpower supply device adjust, according to at least one of the outputvoltage and output current of the step-down circuit, at least one of avoltage value and a current value of a current provided to the voltageconverting circuit.
 7. The wireless charging apparatus of claim 1,wherein the first control circuit is further configured to communicatewith the device to-be-charged to determine a charging mode, wherein thecharging mode comprises a first charging mode and a second chargingmode, and a maximum transmission power of the wireless transmittingcircuit in the first charging mode is higher than that in the secondcharging mode.
 8. The wireless charging apparatus of claim 1, furthercomprising: rectifier-filter circuit, configured to covert analternating current (AC) voltage received from a power supply deviceinto a direct current (DC) voltage; and a DC-DC converter, configured toadjust the DC voltage outputted at the rectifier-filter circuit to afixed magnitude and provide the voltage adjusted as the input voltage tothe voltage converting circuit.
 9. The wireless charging apparatus ofclaim 1, further comprising: a power storage module, configured to storeelectrical power obtained from outside and provide the electrical powerstored to the wireless transmitting circuit; wherein the wirelesstransmitting circuit is further configured to generate theelectromagnetic signal according to the electrical power received fromthe power storage module.
 10. A device to-be-charged, comprising: abattery; a wireless receiving circuit, configured to receive anelectromagnetic signal from a wireless charging apparatus and convertthe electromagnetic signal into an output voltage and an output currentof the wireless receiving circuit; a step-down circuit, configured toreceive the output voltage of the wireless receiving circuit anddecrease the output voltage of the wireless receiving circuit to chargethe battery; a detecting circuit, configured to detect at least one ofan output voltage and an output current of the step-down circuit; and asecond control circuit, configured to communicate with the wirelesscharging apparatus according to at least one of the output voltage andthe output current of the step-down circuit detected by the detectingcircuit, whereby the wireless charging apparatus adjusts a transmissionpower of the electromagnetic signal to make a voltage difference betweenan input voltage of the step-down circuit and the output voltage of thestep-down circuit meet a preset condition.
 11. The device to-be-chargedof claim 10, wherein the battery comprises N cells coupled in series,wherein N is a positive integer greater than one.
 12. The deviceto-be-charged of claim 10, wherein the step-down circuit is a Buckcircuit or a charge pump.
 13. The device to-be-charged of claim 10,wherein the second control circuit is further configured to send,according to at least one of the output voltage and the output currentof the step-down circuit detected by the detecting circuit, adjustmentinformation to the wireless charging apparatus, wherein the adjustmentinformation is used for instructing the wireless charging apparatus toconduct at least one of a current adjustment and a voltage adjustment onelectrical power received from a power supply device, to adjust atransmission power of the electromagnetic signal.
 14. The deviceto-be-charged of claim 10, wherein the device to-be-charged furthercomprises: a converting circuit, configured to receive the outputvoltage and the output current of the wireless receiving circuit andconduct at least one of a constant-voltage control and aconstant-current control on at least one of the output voltage and theoutput current of the wireless receiving circuit to charge the battery;and the second control circuit is further configured to controlswitching between the step-down circuit and the converting circuit. 15.The device to-be-charged of claim 14, wherein the second control circuitis further configured to communicate with the wireless chargingapparatus to determine to control one of the step-down circuit and theconverting circuit to work.
 16. The device to-be-charged of claim 15,wherein the second control circuit is configured to: communicate withthe wireless charging apparatus to determine a charging mode, whereinthe charging mode comprises a first charging mode and a second chargingmode, and a charging speed in the first charging mode is higher thanthat in the second charging mode; and control the step-down circuit towork when the first charging mode is enabled to charge the battery, orcontrol the converting circuit to work when the second charging mode isenabled to charge the battery.
 17. The device to-be-charged of claim 14,wherein the second control circuit is further configured to controlswitching between the step-down circuit and the converting circuitaccording to a temperature of the battery.
 18. The device to-be-chargedof claim 10, wherein the output current of the step-down circuit is aconstant direct current, a pulsating direct current, or an alternatingcurrent.
 19. The device to-be-charged of claim 10, wherein the step-downcircuit is arranged in a first charging channel, the detecting circuitis configured to detect at least one of a voltage and a current in thefirst charging channel and provide voltage value and/or current valuedetected to the second control circuit, and the second control circuitis further configure to provide the voltage value and/or current valuedetected to the wireless charging apparatus for transmission poweradjustment.
 20. A method for wireless charging, being applicable to adevice to-be-charged, the method comprising: receiving, with a wirelessreceiving circuit, an electromagnetic signal from a wireless chargingapparatus and converting the electromagnetic signal into an outputvoltage and an output current of the wireless receiving circuit;receiving, with a step-down circuit, the output voltage of the wirelessreceiving circuit and decreasing the output voltage of the wirelessreceiving circuit to charge a battery of the device to-be-charged;detecting at least one of an output voltage and an output current of thestep-down circuit; and communicating with the wireless chargingapparatus according to at least one of the output voltage and the outputcurrent of the step-down circuit detected, whereby the wireless chargingapparatus adjusts a transmission power of the electromagnetic signal tomake a voltage difference between an input voltage of the step-downcircuit and the output voltage of the step-down circuit meet a presetcondition.